The present invention relates to a superfinishing apparatus and, in particular, relates to a superfinishing apparatus suitable for superfinishing the inner and outer rings of roller bearing.
Conventionally, as an apparatus for superfinishing the inner ring of a tapered roller bearing, a superfinishing stone head vibration apparatus of a superfinishing machine equipped with a vibration mechanism is proposed as shown in FIG. 4 (see the patent document 1, for example).
The superfinishing stone head vibration apparatus of the superfinishing machine is arranged in a manner that right and left vibrators 3, 3 for supporting a superfinishing stone 11 is suspended by a pair of round bar guides 2, 2 through hair bearings 4, 4, respectively. A cam shaft 5 is disposed between the right and left vibrators 3, 3.
As shown in FIG. 5, the cam shaft 5 is provided with vibration rings 15, 15 having a pair of eccentric cams 6, 6 which are made eccentric equally in the opposite directions to each other. As shown in FIG. 4, the vibration rings 15, 15 are held in a manner that they are sandwiched so as to reciprocally move freely by springs 7, 7 which press the right and left vibrators 3, 3 towards the eccentric cams 6, 6, respectively.
Incidentally, in FIGS. 4 and 5, a reference numeral 1 depicts a frame, 8 an adjusting screw, 9 an engagement portion, 10 a superfinishing stone head, 12 a rod, 13 a cylinder, 14 an operation button, 16 a tapered shaft portion and 17 a bolt.
This superfinishing stone head vibration apparatus makes it possible to vibrate at a high speed without causing any friction thereby to improve the durability of the machine, and further can easily obtain uniform and fine surface roughness and correct roundness.
Further, apparatus for finishing a rib and a raceway of an inner ring of a tapered roller bearing is proposed. (see the patent document 2, for example) According to the apparatus, the raceway pressurizes a conventionally known horn-type superfinishing stone, and traverses the superfinishing stone along a groove of the raceway with applying minute vibration to finish the groove.
On the contrary, a rotating conical trapezoidal grinding wheel is used for a rib to make a desired spherical form. Namely, since the process of a rib makes a form, the process is similar to grinding, and it is difficult to improve roughness of the rib. Further, by rotating the grinding wheel, a spindle mechanism is needed, and the apparatus becomes complicated.
Further, an apparatus for simultaneously processing a rib and a raceway of an inner ring of a tapered roller bearing is proposed. (see the patent document 3, for example) The apparatus is characterized in that the inner ring of a tapered roller bearing is applied and exhausted with being in a horizontal status. Due to being in the horizontal status, the inner ring does not fall down, and miss-loading is hardly caused.
However, a size of the apparatus becomes large due to simultaneous process of a raceway and a rib, and an operationality becomes worse.
[Patent Document 1]
Examined Japanese Patent Application Publication No. Sho51-12157
[Patent Document 2]
U.S. Pat. No. 4,222,203 (Unexamined Japanese Patent Application Publication No. Sho54-15594)
[Patent Document 3]
Japanese Utility Model Application Publication No. Hei3-11556
However, recently, according to a high accuracy of a tapered roller bearing, superfinishing process is adopted in order to improve roughness of a rib. Further, apparatuses for simultaneously processing a raceway and a rib of an inner ring of a tapered roller bearing are developed.
According to such apparatuses, if conventional superfinishing stone head vibration apparatus are mounted on a raceway and a rib thereof, the apparatuses grow in size and cost becomes high.
Furthermore, when the size of the apparatus becomes large, a distance between the front surface side to the processing portion of the apparatus becomes long, so that such a problem in use occurs that the exchange of the superfinishing stone 11 and the exchange of a jig tool becomes difficult.